1. Field of the Invention
The present invention relates to an apparatus and a method for manufacturing a semiconductor device, and particularly a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method used when a semiconductor pellet or semiconductor chip is joined to a package.
2. Description of Related Art
FIG. 1 is a schematic cross-sectional view showing the conventional semiconductor device manufacturing apparatus and method used for joining the semiconductor pellet or semiconductor chip to the package. In a conceptual construction of a system shown in FIG. 1, reference numeral 1 denotes a package, 2 a semiconductor pellet, 3 a low-melting point soldering member, 7 a metallized surface layer of the semiconductor pellet, and 10 a heater.
According to the conventional semiconductor device manufacturing apparatus and method, during a joining process, the semiconductor pellet 2 and the package 1 are joined to each other as follows. That is, as shown in FIG. 1, the semiconductor pellet, 2 is mounted on the package 1, and the low melting-point soldering member 3 of AuSn or the like is heated by the heater 10. The low-melting point soldering member 3 is left while heated for a predetermined time under the condition that the temperature is fixed to about the melting point of the low-melting point soldering member 3 (for example, 320.degree. C. in the case of AuSn), thereby joining the semiconductor pellet 2 to the package 1 by the melted low melting-point soldering member 3.
In such conventional semiconductor device manufacturing apparatus and method for joining the semiconductor pellet to the package, the semiconductor pellet 2 is heated and left at the melting point of the low melting-point soldering member 3 (for example, about 320.degree. C.) at at least its joining surface to the package 1. This temperature under the joining process is higher than a temperature under the actual service condition of the semiconductor pellet (for example, about 130.degree. C. in the case of FET or the like). Accordingly, stress is applied to the semiconductor pellet 2 by the low melting-point soldering member 3 and the package 1 due to the difference between the temperature condition in the joining process and the temperature condition at the actual use time of the semiconductor device and the difference in thermal expansion coefficient between associated parts, and this reduces the lifetime of the semiconductor pellet 2.